With rapid development of technology and people's awareness of environmental protection, rechargeable batteries are becoming increasingly popular as power sources in various devices, for instance, mobile phones, laptop computers, power tools and electric automobiles.
Electric automobiles and energy storage power stations generally need high capacity rechargeable batteries as power sources. In addition to high capacity, generally, a rechargeable battery should also have excellent safety performance and long cycle service life, so as to meet different requirements of actual use.
To ensure safety performance of a rechargeable battery, a rechargeable battery is generally provided with a pressure relief valve. When accident occurs due to improper charging, short circuit or exposure to high temperature, high-energy rechargeable battery will produce a lot of gas and a sharp rise in temperature. The high pressure gas opens the pressure relief valve to achieve the purpose of pressure relief Although the arrangement of the pressure relief valve can improve the safety performance of a rechargeable battery, the energy accumulated in a rechargeable battery with accident itself cannot be released. Therefore, the battery itself is a security risk. If the battery is continued to be overcharged after accidents, it will lead to serious safety accidents.
What is needed, therefore, is to provide a rechargeable battery having desirable safety performance.